said calmly, "go after it and put it on in the water. Clear your
mask and snorkel, then come back to shore with full gear on and
operating. No surfacing to take a breath. Use only the snorkel."

Jan looked into the water thoughtfully. The moments ticked by. Finally
Rick asked, "What is it?"

The girl smiled. "I'm planning how I'll do it. If I don't plan in
advance, it will be too late after I've started, and I intend to do it
right the first time."

Rick, Barby, and Scotty exclaimed together, "Good girl!" They
laughed, and Rick explained, "That's what makes a safe diver. Know
what you're going to do before you have to do it."

Jan filled her lungs and dove. The three swam out over her and watched
through their masks. She found the mask, and there was a bad moment
when she got it on upside down, but she quickly reversed it, held it
to her face, and blew it clear. Only then did she bother with the
strap that held it.

Rick watched, pleased. He hadn't told her it wasn't necessary to
attach the mask before clearing. She put the snorkel mouthpiece in
place, but did not bother to attach the rubber strap to her head.
Then, working smoothly but without waste of time, she slipped on the
fins and flashed to the surface. The snorkel emerged and she blew it
clear, then swam to the beach.

"Perfect," Rick applauded.

"You're a natural," Scotty added.

Barby just beamed.

Jan was obviously pleased at their praise, but she was a little shy,
too, so she contented herself with smiling her thanks.

"Aqualung instruction tomorrow morning," Rick said. "Come on. I've
worked up an appetite."

That evening Rick began work on the radio circuits, as he had promised
Barby. The transmitters would be the easiest part, since he could use
the same circuits that had gone into the design of the Tractosaur
controls, modified only slightly for use on the highest amateur band.
Fortunately, Rick had both an operator's and station licenses as a
radio "ham," so Barby's scheme wouldn't mean illegal operation.

The girls wandered into the shop where he and Scotty were at work, but
there was nothing exciting about the painstaking work of laying out
diagrams, so they soon left.

Scotty paused in his work of assembling the parts they would need.
"Rick, how about making transceivers instead of simple transmitters?"

"So we can send and receive on the same unit? We can do it, all right.
But why?"

"I was just thinking. Quite a few times we'd ha